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    Help setting proper pressure for steam boiler. (19 Posts)

  • Access Access @ 11:01 PM
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    Help setting proper pressure for steam boiler.

    I have a Honeywell L404A pressure control with settings you see on the photo below. I have cast iron baseboards all around two story house and all of them are hot while running at full steam. It seem like it gets pretty even heating, however there are some problems.
    Specifically it’s water hummer, short-cycling. Also there is some water inside baseboards, since I can hear gurgles and sometimes water comes out from air valves. Heavy water hammering is mostly on the first floor of the house, the second floor just has some gargling.
    I’ve read that high pressure can lead to hammering sounds as well condensate to stay up in the system.

    What should I set the “MAIN” psi setting? Also what “DIFF” scale indicates and what should it be set to?

    Thanks in advance.
  • JStar JStar @ 11:07 PM
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    RE

    Oh boy, that's high!

    Set the main at 1 psi. Set the differential at 1 psi. It's not printed, but go halfway between 0 and 2. You may have to fine tune it later on if it causes problems. You should never need to run above 2 psi on a residential boiler.

    Main is the cut-out pressure. Differential is the number subtracted from the main, and sets the cut-in pressure.
    - Joe Starosielec
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    This post was edited by an admin on December 21, 2011 11:09 PM.
  • Access Access @ 11:53 PM
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    RE 1

    Thanks for your reply.
     
    I just set 1 on MAIN and 1 for DIFF and now it seems to be on very short-cycling. Shuts down every 1 minutes, wait like 20-30 seconds then start up again.
     
    How should I adjust it now?
     
    Thank you
    This post was edited by an admin on December 21, 2011 11:54 PM.
  • nicholas bonham-carter nicholas bonham-carter @ 11:40 PM
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    Hammering under pressure

    Also check your main vents, as that pressuretrol may have been set high to squeeze the air out of the pipes.
    You would benefit as well from having a good low pressure gauge (gaugestore.com 0-3psi. Only with that gauge can you know what pressure you have.--NBC
  • Access Access @ 11:58 PM
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    RE

    Hi,
    The pressure gauge not moving at all, it stays at the bottom of the cylindrical visible gauge. It's when I have my original setting that you can see on the attached photo.
    Thanks
  • nicholas bonham-carter nicholas bonham-carter @ 12:53 AM
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    pressure gauge

    i was refering to the pressure gauge which shows pressure on a round dial, not the pressure control, which controls the high and low settings.
    next step with your system would be to check the main vents [usually on the pipes coming back to the boiler. my guess is that they are not allowing the air to escape easily, and therefore the boiler is doing their work.--nbc
  • Steamhead Steamhead @ 9:29 AM
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    How long does it take

    for the boiler to start short-cycling? Do the radiators all heat fully before it short-cycles?
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  • Access Access @ 10:22 AM
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    RE:How long does it take

    Hi,

    It's doesn't start short-cycling right away, it takes about 7 minutes to start doing that. Radiators aren't fully heated yet either. It seems like it is somewhere close to the middle of the process.

    Thanks
  • Access Access @ 10:22 AM
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    RE:How long does it take

    This post was edited by an admin on December 22, 2011 10:59 AM.
  • JStar JStar @ 7:57 PM
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    RE

    Do you have any steam leaks? At the radiators, or in the piping? If the steam leaks out fast enough it may be dropping pressure very quickly. Is the boiler losing water during its cycle?

    You can also try to raise the main PSI setting to a point where it settles out. But the lower the better.
    - Joe Starosielec
    http://thatcherhvac
    http://facebook.com/thatcherhvac



    Guaranteed performance. Guaranteed energy savings.


    Serving all of NJ, NYC, Southern NY State, and eastern PA.

    Consultation anywhere.

    (Formerly "ecuacool")
    This post was edited by an admin on December 22, 2011 7:58 PM.
  • Access Access @ 9:52 PM
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    RE

    No, there are no leaks at all and it doesn't loos water either.

    Here is a little info about my setup. I have 170K BTU Burnham boiler. My leaving room is about 400 sf and there are two 5ft long baseboards and one 3ft one. On the second floor there are 3 bedrooms. Two bedrooms have 5ft long and one room has 3ft one.

    Can it be that my boiler is too big, and it's ability to produce steam exceeds the system's ability to condense steam?

    Thanks
  • Charlie from wmass Charlie from wmass @ 10:09 PM
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    Do you have any other radiators?

    or baseboard. What you list is about 22kbtu's of heat and your boiler is 170Kbtu's. That's some way over sized boiler. Does the house heat up?
    Cost is what you spend , value is what you get.
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  • Access Access @ 10:24 AM
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    RE: Do you have any other radiators?

    >Do you have any other radiators?
    No, just those are listed.

    >Does the house heat up?
    Now, when outside temp is about 35F, it can make to 70 relatively easy, but at Jan, Feb it almost impossible get to 70F.
  • Charlie from wmass Charlie from wmass @ 10:13 PM
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    I wonder if the high pressure

    is due to the lack of radiative surface area, so they cranked the pressure to try and get more btu's from each square foot. The vents are most likely rated no more than 3 pounds of pressure.
    Cost is what you spend , value is what you get.
    cell # 413-841-6726
    This post was edited by an admin on December 22, 2011 10:16 PM.
  • olskool721 olskool721 @ 11:59 AM
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    gas fired boiler differential issues

    My heating system works. I had an issue that a tech corrected by making a slight adjustment t the Main-Differential controller. This is an old Honeywell control attached to a Minneapolis-Honeywell cut out valve. I have the settings at 2psi for main and 1psi for diff. The "call for heat" is active yet the boiler is not being fired up. The gas is flowing cause the pilot is lit. Please help. I have attached a photo to assist with my explanations. The "main-diff" control is to the per right on image. Thanks for your help. I know the systems is old, but keeps old Victorian nice and warm.
  • nicholas bonham-carter nicholas bonham-carter @ 9:14 AM
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    New thread needed

    Best to start a new thread for this, so it does not get lost.
    There is nothing wrong with old boilers/systems, as long as they are maintained regularly. Has the tech been back to look at the problem? One of the safety devices on the boiler is apparently not allowing the boiler to fire, and he will need to find which one.--NBC
  • olskool721 olskool721 @ 10:40 AM
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    thanks for help

    Thanks for the suggestion. Yes the tech was back, and I am still having a small issue. The furnace does fire and run. Main thing is that I will get thru winter. Then I can look deeper into repair/replacing the burner/boiler/water tank set up.
    olskool
  • olskool721 olskool721 @ 10:55 AM
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    new thread started

    http://www.heatinghelp.com/forum-thread/149090/help-with-setting-pressure-differential-and-cut-out-valve

    as suggested, I started a new thread so as to not get lost.  I will mention the safety switch to my tech! Thanks!
  • Deeh Deeh @ 6:46 PM
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    Presure Control Problem

    I have a Carrier Steam Boiler that I bought in 2011, radiators and baseboard radiators. The boiler was working perfect until a technician adjusted the PSI to 1.0 and he set the water level below the suggested water line.  Now my boiler shut off every 10 minutes and takes twice as lone to heat the house.  The technician has been to the house several times and said that the water level is low which causes the boiler to shut down.   The boiler technician did a high pressure cleaning of the boiler and cleaned the pig tail. Ok so I made sure that the water level was at the manufacturer suggested water line and the boiler still shuts down.  The water level was at or above the manufacturer's water line when it shut down. I'm thinking if I adjust my Honeywell Pressure Controller higher to PSI of 2.0 or 2.5 this could solve the problem.?
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